Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1101 AM EST Sat Nov 13 2021 Valid 12Z Tue Nov 16 2021 - 12Z Sat Nov 20 2021 ...Overview and Guidance/Predictability Assessment... A progressive flow regime, with troughing amplifying mid-continent Wednesday and next Saturday, will be seen this period. While detail issues remain, the 06z GFS/00z ECMWF/00z UKMET fit best with the ensemble means, with the 00z Canadian falling out of favor as early as Wednesday with its more progressive flow pattern. With some amplification expected at times, quicker does not seem best. The pressures, precipitation forecast, winds, and 500 hPa heights were primarily derived from the 06z GFS, 00z UKMET, 00z ECMWF, and the 00z NAEFS/ECMWF ensemble means. The remainder of the grids relied heavily on the 13z National Blend of Models guidance. ...Weather/Hazards Highlights... Expect mostly light to moderate rain and higher elevation snow over the northern Rockies early Tuesday in association with the upper trough/leading cold front pushing through the region before fading. The potent surface low tracking across southern Canada Tuesday onward will bring a period of strong/gusty winds to northern tier areas, especially the Northern Plains on Tuesday into Wednesday. Moisture should increase ahead of the low's trailing cold front from midweek onward, leading to mostly light/moderate rain over portions of the Mississippi, Ohio, and Tennessee Valleys along with some light precipitation in the Great Lakes region. The southern Florida Peninsula should increasing rainfall mid-late week as moisture interacts with a stalled front to the south. Some precipitation should reach the West late week, but for the moment only modest amounts are expected. The Midwest should see moderate precipitation late Friday-Saturday as the western system sweeps eastward. Well above normal temperatures will continue into Tuesday over the Plains and southern half of the West. The warmest readings versus normal should be over the Plains where plus 15-25F anomalies will be common and some daily records for highs/warm lows will be possible. Currently the best potential for highs to approach/reach record values is over the western half of Texas. As the cold front emerging from the Northeast continues onward, warmth will extend into the South and East Wednesday-Thursday but in modified form with highs/lows generally only up to 10-15F above normal. Cooler air behind the front will spread mostly 5-10F below normal temperatures across the central and eastern U.S. from Wednesday through the rest of the week. Roth/Rausch/Tate Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, winter weather outlook probabilities and heat indices are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml